Add --commitish option to specify target_commitish branch

[Susheer]

Problem

The target_commitish parameter is hardcoded to 'master', causing issues when the default branch is different.

Solution

• Added a --commitish option to allow users to specify the branch for the target_commitish parameter.
• If the --commitish option is not provided, it defaults to 'master'.

Changes Made

• Updated the publish command to include the --commitish option.
• Modified the logic to use the value provided by --commitish or default to 'master'.

Testing

• Tested with repositories having different default branches.
• Verified that the --commitish option correctly sets the target_commitish parameter.
• Ensured that the tool defaults to 'master' if the --commitish option is not provided.

Usage

node-pre-gyp-github publish --release --commitish main
or 
node-pre-gyp-github publish  --commitish main